/*
 * Copyright (C) 2007-2010 Geometer Plus <contact@geometerplus.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

package org.geometerplus.zlibrary.core.encoding;

import org.geometerplus.zlibrary.core.filesystem.ZLResourceFile;
import org.geometerplus.zlibrary.core.xml.ZLStringMap;
import org.geometerplus.zlibrary.core.xml.ZLXMLReaderAdapter;

import java.util.HashMap;

public final class ZLEncodingCollection {
    private static ZLEncodingCollection ourInstance;

    public static ZLEncodingCollection Instance() {
        if (ourInstance == null) {
            ourInstance = new ZLEncodingCollection();
        }
        return ourInstance;
    }

    private final HashMap<String, String> myEncodingByAlias = new HashMap<String, String>();

    private ZLEncodingCollection() {
        new ZLEncodingCollectionReader().read(
                ZLResourceFile.createResourceFile("data/encodings/Encodings.xml")
        );
    }

    public String getEncodingName(String alias) {
        final String name = myEncodingByAlias.get(alias);
        return (name != null) ? name : alias;
    }

    public String getEncodingName(int code) {
        return myEncodingByAlias.get("" + code);
    }

    private class ZLEncodingCollectionReader extends ZLXMLReaderAdapter {
        private String myCurrentEncodingName;

        public ZLEncodingCollectionReader() {
        }

        public boolean dontCacheAttributeValues() {
            return true;
        }

        private static final String ENCODING = "encoding";
        private static final String NAME = "name";
        private static final String ALIAS = "alias";
        private static final String CODE = "code";
        private static final String NUMBER = "number";

        public boolean startElementHandler(String tag, ZLStringMap attributes) {
            if (ENCODING == tag) {
                myCurrentEncodingName = attributes.getValue(NAME);
            } else if (myCurrentEncodingName != null) {
                String alias = null;
                if (ALIAS == tag) {
                    alias = attributes.getValue(NAME);
                } else if (CODE == tag) {
                    alias = attributes.getValue(NUMBER);
                }
                if (alias != null) {
                    myEncodingByAlias.put(alias, myCurrentEncodingName);
                }
            }
            return false;
        }

        public boolean endElementHandler(String tag) {
            if (ENCODING == tag) {
                myCurrentEncodingName = null;
            }
            return false;
        }
    }
}
